During the work performed within the SafeT project a clear lack of validated information on tunnel accidents was identified. Consequently, with insufficient data to provide the information necessary to detect trends or point towards possible prevention and mitigation measures, the lessons to be learned - in particular with respect to the identification of accident root causes - are very limited. This finding fed into the development of recommendations for the collection of data on tunnel accidents for use by authorities, tunnel operators or owners. By its very nature the template development also guided the formulation of recommendations for the investigation of accidents as the accident-investigation report should be the primary source for data collection via the template and should drive the template's regular updating. Article 15 on Reporting of the EU Directive, to which the results of Work Package 4 are most pertinent, is very specific in contents without, however, spelling out how the objectives of the Article should be achieved. Therefore, based on the findings of Work Package 4 guidelines have been developed to support the effective implementation of Article 15 by providing guidance to the actors responsible for reporting or sharing information under the EU Directive.